Rotary airfoil



Aug. l5, 1933. s. RosENBERG ErAL 1,922,865

ROTARY AIRFQIL Fired 'April 22, 1952 4 sheets-sheet 1 lNvENToRs Sandal' asaz l gewandt? Klemm ATTORNEY Aug. l5, 1933.

s. ROSENBERG El' AL ROTARY AIRFOIL Filed April 22', 1932 4 sheets-sheet 2 INVENToRs afzdar Zasen rrg 191g? r 576111111/ ATTONEY Augl15, 1933- s. RosENBERG Ei- AL 1,922,866

YROTARY AIRFOIL Filed April 22, 1932 4 Sheets-Shea?I 3 ENToRs sener Sande r lexande r Klemm,

Aug. l5, 1933. s. RosENBERG Er AL ROTARY AIRFOIL Filed April 22, 1932 4 Sheets-Sheet 4 .Sandor sezzrr fllexand ATTORNEY Patented' Aug. 15, 1933 ROTARY AIRFOIL' Sandor RosenbergA and Alexander Klemin, New York, N. Y.

application anni zz, im. serial No. 606.841

' s own. (ci. 244-19) As distinct from the airplane there are several types of aircraft in which rotating airfoil systems are employed. Some of these rotating airfoil systems are of the power driven type'and aretheni termed helicopter or direct lifting machines, and others are of the free rotor type in which the surface rotates under the action of air pressures.

Inallsuchtypesofaircra.ft,ama.ximumdi ameter and a maximum area of the'supporting i surfaces are desirable attake-off, on landing. and to some extent on the climb whether vertical or inclined. On the other hand in any forward ilight it is desirable from the point of view of A v emcieney that the area and diameter of the rotarysystem be reduced, as thereby the drag of the rotary system is decreased and the flight speed increased,`or the fuel consumption decreased at a given speed. v

It is the essence of the invention that a varia-- obleareaandvariablediameterwillbeincorporated in these types of aircraft. We provide such variable area inapplication to all types of rotary airfoil `mbasicmlncip1eoiexnsionofareaandx 5 diameterforexamplemaybeappliedtothe'auto- .,--gyrotypeof aircraft,inwhichtherotarysys temisfreetorotateaboutasubstantiallyverticalaxisandatthesametlmethebladesarefree' to oseillate up and down abouta substantially` D horizont-alexis. Y

Ourinventionmayalsobeapplied tothesocalledrigidrotorinwhichthebladeisfreeto rotateaboutaverticalaxisandthebladeson opposite sides are continuous and free to pivot I5 about a substantially horizontal am.

Our inventionis also aplilicabletothefeatheringtypeof freerotor'inwhichthebladesystem isfreetoturnaboutasubstantlallyverticalaxis, while at the same time free to feather or oscilme about the ma which coincides with the 1ongltudinal axis of the'blades, but in which sys- .v temthlecenterofpressureoneithersideisbehind the featheringaxis so that the blades are made to feather.

ommvenucnis mappueabletoinattypeof rotating airfoil system in which the blades are made to feather, cally by some means of mechanical control.

Our invention is also applicable to the rotating 5 systeminwhich powerisappliedtoasubstantially vertical shaft to which the blades are rigidly keyed. It is applicable to all variations of such power driven rotary It is also applicable to those power driven sys- .55 tems in which, -wniie power is applied to a verucal shaft, the blades themselves are free to oscillate about their own longitudinal axis and are provided with some form of controlling or stabilising surface in rear of the main blades.

The fundamental principle involved in our invention is that the area and diameter ofthe blades may be varied at will in a`. number oflways. Our invention also embodies the case where it is desired to vary the diameter without varying the actual area of the blades.

Having stated the broad principles of the in,

vention, which consist in varying the diameter,

or the area, or both, at will, we show hereinafter some embodiments of the means for carrying out this invention.

Other features and advantages of our invention will hereinafter appear.'

In the drawings:

Figure 1 is a horizontal sectional view of opposed blades forming the aerodynamic elements in a rotor; wherein the tip portions are slidable in and out to vary the blade areas and diameter, and control means therefor. f

Fig. 2 is a sectional elevation thereof.

Fig. 3 is a perspective view of the control means.

Fig. 4 is a section on the line 4 4 of Fig. 1.

Fig. 5 is asection on the line 5-5 of Fig. 2.I

Fig. 6 is a horizontal section of a rotor having telescopic blades, as extended.

Fig. 7 is a sectional elevation thereof.

Fig. 8 is a planview, partly in horizontalsection, showing the blade sections collapsed.

Fig. 9 is a horizontal sectional view of a rotor whose blades have tip portions that Vare slidable in and out, and-which are'capable of changing their pitch settings whilst thus varying the area and diameter of the blades. Y

Fig. l0 is an'enlarged, partial section thereof, showing the control means.

Fig. 11 is a side sectional view of Fig. 10. Fig. 12 is a side elevation of a rotor whose entire blades are slidable to vary their diameter.

Fig. 13 is a similar, enlarged partial view, showing the control means, and

Fig. 14 is a side sectional elevation-of Fig. 13.

Treating first of that form of our invention 'nsl illustrated in Figures 1 to 5, let 1 indicate a holposed in slidable relation to the blade portions '2, 2. As here shown the tip portions 3, 3 are slidable within the blade portions 2, 2 and said tip portions are movable in and'out by suitable control means that may be actuable by the pilot.

By way of example we have shown the parallel rods 4, 4, connected at their outer ends with the interior of each tip portion 3, and extending through a bridge or membrane 5, the inner ends of said rods having a connecting cross-piece 6 which opposes the inner surface of bridge 5. A pulley 7 for each blade, mounted at the outer surface of a bridge 5, co-acts with a pulley 8, carried by a shaft 9 that is journalled in. the rotor hub 10, for the in and out sliding movements of the tip portions, these movements being performed through the medium of a cable 11, that is passed over pulleys 7 and 8 and whose ends are connected respectively to the opposite sides of cross-piece 6.

A sprocket wheel 12 is carried by the shaft 9, and located intermediate the two pulleys 8, said sprocket 12 connecting, by a sprocket chain 13, with a sprocket Wheel 14 that is mounted on a pivot 15 in a fixed position within shaft 1. Pivot .15 also carries a pinion 16 that is in mesh with a rack bar 17, which is slidable in a guide 18, said rack bar carrying at its lower end a plunger 19, which is slidable on guides 2O in shaft 1, to be non-rotatable therein, while a control rod 21 engages said plunger 19, to move it and the rack bar up and down, said rod 21 having a circular head 22 which is loosely retained in a bearing provided 'therefor in said plunger, so that the control rod may not rotate with the rotor.

In the modified form of our invention illustrated in Figs. 6 to 8 we have shown a rotor having the upwardly extending, hollow shaft 23, having a hub portion 24, from which there extend laterally the hollow blade sections 25, 25. Slidable in each of the blade sections 25 is another blade section 26, and these latter blade sections themselves each carry a further blade section or tip portion 27. The blade sections 26, 27 are each respectively retained in their extended positions as by means of root enlargements 28 thereon that are adapted to engage inward shoulders 29 located near the outer ends of their adjoining sections.

There is thus presented that feature of our invention wherein a number of blade sections have telescopic relation, so that, the rotor blades thus constituted, may be at will extended to their full efficient area and diameter, or contracted to a relatively small diameter for the purpose of presenting the least possible head resistance in speed flight.

Also, in this phase of our invention we have typified the employment of centrifugal force for extending the blades out to their maximum radius, while relying on mechanical means fo reducing their radius.

Since the blade sections are freely slidable one within another, the centrifugal force set up in rotation has the effect of extending the sections to the full blade length, as is obvious.

For the purpose of contracting the blades we attach a cable 30 to each of the blade tip portions 27, as at 31, leading said cable through the hollow sections to the hub interior, where it is passed over an idler 32, and around a sheave 33, the free end of said cable being connected with an eye bolt 3'4, that isvprovided with a terminal sphere 35.

It will be seen that there are two sheaves 33, both acting with a separate cable 30 for the respective blades.

The sphere 35 is engaged, in relatively revoluble relation by a socket member 37, that is carried by a plunger 38, said plunger lying loosely in shaft 23, to be in non-rotative relation therein, and said plunger is engaged by a flexible connector 39, for its manipulation by the pilot.

Hence it will be appreciated that by drawing upon plunger 38, thereby the blades may be reduced in diameter and likewise in area.

In Fig. 8 we have shown blade sections as fully collapsed.

In still another form of our invention we have found it practical to modify the pitch of the rotor blades at the time of varying the area and diameter thereof, to in this way accord the blades a diminished or increased angle when reduced in area and diameter, thereby modifying the resistance they offer; and to give said blades a suitable angle of incidence when extended for lift or support.

As an example of means for accomplishing these results we have illustrated, in Figs. 9 to 11, a concrete example of mechanism suited to the purposes set forth. r

Thus, there appears in said figures a hollow, upwardly extending shaft 40, with which is connected a hollow hub 41, having laterally extending bearing portions 42, in which are respectively journalled the tubular members 43, that are fitted 105 in the root portions 44 of rotor blades which respectively carry the slidable blade tip portions 45. The non-rotatingA connection between the members 43 and blade portions 44 may be effected by splines 46, and nuts 47, threaded upon the ends of members 43, co-act with the end Walls 48 of blade portions 44, to serve as thrust bearings therefor.

The blade portions, thus rendered revoluble, each has its tubular member 43 provided with a gear 49 which meshes with a pinion 50, carried by a shaft 51 that is journalled in bearings 52 within the hub, said shaft bearing a helical thread 52 that meshes with a helical gear 53, mounted on a Shaft 54, which is journaued in the hub, and 120 disposed intermediate the two shafts 51, transversely thereof.

Sheaves 55, carried by the shaft 54, and disposed at opposite sides of gear 53, each have a cable 56 thereon, said cable being extended 125 through the shaft 40 for manipulation' by the pilot, and said cables respectively being extended, from their sheaves, through the tubular members 43, and the blade portions 44, to the slidable tips 45, with which latter they are connected, as at 57. 130

Thus the action of pulling upon cables 56 has the effect of rotating gear 53, and of sliding the blade tips inwardly. Also the rotation of gear 53 and the gear train, whilst pulling in the blade tips, is intended to vary the pitch of the blades 135 from an attacking angle toward a zero angle. The converse is the case when the blade tips arer moved outwardly, which in this example occurs through the inuence of centrifugal action, for in this outward movement of the blade tips the cables 140 are caused to rotate the gear 53 oppositely and thereby the gear train turns the blades to accord them a desired angular pitch.

n stillvanother form of our invention, whereby the diameter of the rotor blades may be varied, 1 without changing the area they present, we show, in Figs. 12 to 14, an upwardly extending hollow shaft 58, with which a hub portion 59 is connected, said hub portion having the oppositely extending hollow arms so, in which are sudably 150 tted the stems 61 of blades 62. Said stems 61 each carry a rack bar 63 that are in mesh with a gear wheel 64, at opposite sides thereof, said gear wheel being carried by a shaft 65 that is journalled to the hub 59. Shaft `65 also carries a` -imparted to gear 64.

By the means thus described the blades 62 are moved both in and out, to vary their diameter, under the influence of positive mechanical impulses. Y

It is to be understood that the mechanisms herein illustrated and described for' performing the various functions of extending and contracting the blade areas and diameters in a rotary airfoil system, and for varying the incidence of such blades, are intended as merely typical and are not to be construed as in any Way limiting our invention to the employment of these particular control means.

. Variations within the spirit and scope of our invention are equally comprehended by the foregoing disclosure.

We claim:

1. A rotor havingl airfoils composed of interengaging, longitudinally slidable sections, to be capable of expansion under the influence of centrifugal force, said airfoils being revoluble about their longitudinal axes, to modify their pitch settings, control means for contracting said airfoils, and means lactuated by said control means for coordinating the rotation of said airfoils respectively .with their contracting and expanding operations.

2. A rotor having airfoils composed of interengaging, longitudinally slidable sections,` said airfoils being extensible under the inuence of centrifugal force, and manual irreversible control means for positively retracting and holding said airfoils while in flight in any desired. extent of retraction. y

3. In an air driven rotor airfoils composed of interengaging, longitudinally slidable sections,

' said airfoils being extensible under the influence of centrifugal force, and manual irreversible control means for positively retracting and holding lsaid airfoils while in flight in any desired extent of retraction.

4. In an aerodynamically auto rotating rotor airfoils composed of interengaging, longitudinally slidable sections, said airfoils being extensible under the influence of centrifugal force, and manual irreversible control means for positively retracting and holding said airfoils While in flight in any desired extent of retraction.

5. An aerodynamically rotatable wing system comprising a plurality of wings, means for simultaneously varying the area of all the wings to vary the disk area of the system, and means for selectively varying the area of the wings whereby the moments in the system may be varied.

SANDOR ROSEN'BERG. ALEXANDER KLEMIN. 

